Background

Analysing the status of ecosystem services and their driving mechanisms along environmental gradients is highly important for the reconstruction and protection of regional ecosystems. Exploration of the effects of plant functional traits on ecosystem services is important for revealing the formation mechanisms of ecosystem services. However, the complex effects of plant functional traits on ecosystem services, especially below-ground functional traits, which play critical roles in carbon sequestration, water conservation and soil conservation services, have not been explored in depth.

Methods

Data on plant functional traits and ecosystem services were collected from different vegetation zones (steppe, forest-steppe and forest) in a loess hilly gully region. Two representative small watersheds were selected for field experiments in each vegetation zone, each watershed contains artificial forestlands (Robinia pseudoacacia and Caragana korshinskii) and natural grasslands (i.e., areas that underwent natural recovery after farmland abandonment), and a total of 162 quadrats were set up throughout the study area.

Results

The leaf area and specific leaf area gradually increased from the steppe zone to the forest zone, and the leaf thickness, leaf tissue density, and leaf carbon content gradually decreased across this gradient. The root functional traits (except for root tissue density and root carbon content) of each vegetation type decreased in all the soil layers in the following order: forest-steppe zone > steppe zone > forest zone. The trends of all ecosystem services were consistent with those of leaf area. In artificial forestlands, plant above-ground functional traits had greater effects on carbon sequestration and soil conservation services than did below-ground functional traits, whereas water conservation services were strongly linked with below-ground functional traits. The above-ground plant functional traits in the natural grasslands had greater effects on all the ecosystem services than did the below-ground functional traits.

Conclusions

Natural grasslands are suitable for vegetation restoration in these three vegetation zones. Moreover, it is necessary to plant artificial forests in forest-steppe and forest zones to improve soil conservation and carbon sequestration services to cope with extreme climate change.

中文翻译：

---

植物地上和地下功能性状对人工林地和天然草地跨植被区生态系统服务的影响对比

 背景

分析生态系统服务状况及其沿环境梯度的驱动机制对于区域生态系统的重建和保护非常重要。探索植物功能性状对生态系统服务的影响对于揭示生态系统服务的形成机制具有重要意义。然而，植物功能性状对生态系统服务，特别是地下功能性状的复杂影响尚未得到深入探讨，它们在碳封存、水源保持和土壤保持服务中起着关键作用。

 方法

从黄土丘陵沟壑区的不同植被区（草原、森林-草原和森林）收集了植物功能性状和生态系统服务的数据。在每个植被区选取 2 个具有代表性的小流域进行田间试验，每个流域包含人工林地（刺槐和 Caragana korshinskii）和天然草原（即农田撂荒后自然恢复的区域），在整个研究区共设置了 162 个样方。

 结果

叶面积和比叶面积从草原区到林区逐渐增加，叶厚、叶组织密度和叶碳含量在该梯度上逐渐降低。各植被类型的根功能性状（根组织密度和根系碳含量除外）在所有土层中按以下顺序降低：森林-草原区 > 草原区 > 森林区。所有生态系统服务的趋势与叶面积的趋势一致。在人工林地中，植物地上功能性状对固碳和土壤保持服务的影响大于地下功能性状，而水源保持服务与地下功能性状密切相关。天然草地地上植物功能性状对所有生态系统服务的影响大于地下功能性状。

 结论

天然草原适合这三个植被区的植被恢复。此外，有必要在森林草原和森林区域种植人工林，以改善土壤保护和碳封存服务，以应对极端气候变化。